Wireless receiving system.



A. W. HULL.

WIRELESS RECEIVING SYSTEM. APPLICATION FILED MAR-10.1%].

E 1,291,527. Patented Jan. 1 1, i919.

Fig; l.

Inventor: Albert \X/.Hu.ll

Jog His flttovneg UNI ED STATES PATENT oFFIoE.

ALBERT H ULIJ, 0F SCHENECTADY. NEW YORK, ASSIGNOR TO, GENERAL ELECTRIC'COMPANY, ACOBPORATIQN OF NEW YORK. I

WIRELESS RECEIVING SYSTEM.

Receiving Systems, of which the following is a SPGQlfiCfitlOI};

y present invention relates to means for ampllfylng variable currents.and more particularly to means for amplifying and detectiug currentsproduced by wireless signals in a receiving antenna.

In a paper published in the Physical Rewz'ew of January, 1916, I havedescribed an electron discharge device in which a negacorrespondingvariation in the number of second describ tion Serial No. 47,938, filedAugust 30, 1915.-

- second object of my invention is to provide a receiving circuit .whichwill be cape-- cially adapted for the reception of continuoi. dynemethod.

tive resistance characteristic is obtained by producing, from anincandescent cathode.

-rece1ver a capacity of such value with re current between thetivoelectrod'es in an external circuit varies inversely as thepotential-between the electrodes. With this device 'thevalue of thenegative resistance may.

be varied b varying the temperature of the cathode and thereby varyinthe number of primary electrons produce since a, variation in the numberof primary electrons .which reachthe third electrode will cause aelectrons emitted. This device is and claimed in my prior applica In aprior application, S..N.'101,729, filed June 5, 1916, I have describedand claimed a modification of this device in which the value of thenegative resistance may be v:1-.

ried by varying the potential of a discharge controlling member inproximity to the cathode.

mentioned be utilized I have also shown in the above or receivingwireless signals; The ob ect"of my presentmvention 15 to provide animproved circuit arrangement in which the device described in theapplica-' tion referred tomay be utilized-for receiving wireless si als.whereby'the sensitiveness andselec'tivi of the receiving circuit begreatly increased.

ous wave signals by the so-called hetero.-

Specification of Letters Patent.

Application filed March 10, 1917. Seth 1N0. 154,025.

a plication how this devicemay f characteristic. of my'mventlon arepointed out with particularity in" the appended inconnection with Incarrying 0ut the first object of my invention I provide inductance andcapacity in Patented Jan .14 1919;:

circuit with the negative resistance, of such values that the circuit isresonant to the radio frequency of the, waves to be received. Thecircuit is so arranged that oscillations will not be produced unless thevalue of the. nega tiv'e resistance is greater or less than a certaincritical value. When the circuit is arranged in this way and receivedoscillations {are impressed upon a controlling grid, the value of thenegative resistance,.,w1ll healtered in such a way that oscillationswill be produced in the circuit. As a result the selectivity andsensitiveness of the device or signals will 'be' greatly. incre'ased.- Ialso provide in conjunction with the telephone 11 order to provide astill further in? the degree of amplification of the received Inattaining thesecond object of my in.-

vention I arrange the circuit containingftlieZ negative resistance insuch a way that oscil,-.-

lations will be produced therein of a fre quency slightly-different from:the frequenc I of thereceived oscillations. As an the twp sets ofoscillations will combineto" produce beats in the telephone receiver inaccordance with the usual heterod-yne method.

The novel features which I believe to he claims. The invention, itself,however, both as to its organization andmethod of opera} tion, togetherwith further objects and advantages thereof, will best be understood byreference to the following description taken the accompanyin draw-. ingin which Figures 1 and 2 show maticallytwo difierent modifications.

As indicated diagrammatically. in the hawing,- an evacuated receptaclclis provided withfa cathode which is preferably which' may be by means ofthe rent-between the electrodes is not accompanied ,by any visiblemanifestationoil' gas ionization, such for example, as blue low. In theoperation of this device a.de nite positive potential is applied tothean'ode d-by means of the battery 7, the cathfle being considered asat zero or earth potential. If the cathode. is heated to incandescencethere will be a dew-of electrons from cathode to anodeu It the thirdelectrode 5 is at the same potential as the cathode no electrons will bereceived thereby. It,

however, a small positive potential less than that of the. anodeelectrode a portion varies inversol electrodes.-

aplied to the not obattery 8, t,

numbered e ectrons 'andreachzthe third electrode and the current intheextern electrode increases faster than t of primary point,

is applied .to the third of the electrons will pass through the anodeand reach the third electrode; The velocityv with which these electronswill strike the third electrode will depend upon the potentialybetweeuit and the cathode.

If this potential is increased the .vel'ocit will increaseuntil theelectrons, striking t e third electrode, are able, by their impact, to"liberate secondary electrons.

' These secondary electrons leavingthe third electrode will be attractedto the more posithe anode. As the potential is incneased,-

a point" will be reached at which her of secondary electrons-leavin thenumthe third e number electrons received, and the cur;- rent whic will,flow in. the external circuit between the cathode and third will beginto decrease. its the the third electrode is increased and ma pointwtrodea preachesthat even reversein direction u toe of the anode. Thusrange through which it-has anega;

t1 resistancezcharacteristic; that is, over which] he currentin theexternal circuitbetween-the cathode and the third electrode as thepotential between the now a-constant potential is third-electrode, bymeans of current in theefie tentialis between the cathode -and theqdecha'r e -controllinig 81, the which leave the cathode varied, alcircuit will that is,--ji'"'th'e is {made rame positive, the

be ijvariw aecofdingly member .8

bata third electrode 5.

electrode petential of yond this. the current will continue to decreaseere the potential of the thir elecin I we suchzalne that thc'device wopera as a nega ive resistan' ';'"will be ajconstant flow of "-ternalimuitu. If, however, a vafriable po t" em i flow of increase and if themember 6 is made more negative, the flow of electronswill decreaseelectrons to the, third electrodewill I and a small change in "thepotential of the member 6 will be capable oi reducing a 'large chan e"-in the current tween the cathode an the third electrode. a in utilizingthis, device for the reception oi wireless signals, waves which arereceived upon the antenna 9 are impressed upon the discharge controllingmember 6 by an ,oscillatin circuit com. rising an inductance 10 w ich iscouple to the antenna I inductance and a variable condenser "12.

I also provide in the external circuit be-.

meanspf tween cathode and third electrode a variable inductance l3 and avariable capacity 14: in

parallel. 'lhis'circuit may v telephonereceiver l5 s unted by'a variablecondenser 16. In receiving s' als, by this system, the inductance 13 anmay be so adjusted that the circuit is capable of oscillating at afrequency equal to that of the received signals. The value of thenegative resistance is adjusted to such a point that the circuit is neara ointiof in-- stahility or a point where osci begin. When the potentialof the member 6 is varied by received oscillations, the value of thenegative resistance -sufiiciently so that the circuit willstart'oscillatin Under these conditions the ainplification asymetric andthdresulting current will 'op sired indication. Without include, theusual ations. will will be changed of the received signals will hecapacity 14:

the circuit would tendto produce oscillations of an undesirable audio.frequency. condenser 16, however, may as'to prevent the setting up oiaudio frequency oscillations or may he so adjuated'a's to produce audiofrequency .a froquency equal to the group frequency of the incomingwaves. The final adyustments of the system may conveniently beinadevarying the value of the ne varying the temperature Q in case the.system receivin adjust gative resistance continuous waves, itmay.

that continuous from that 'f. the received waves. The two sets ofosciations .duce beats inthe telephone receiver 15;

order to. secure the highest degree of amplification in the symemthepositivei resistance of .tiv'e resistance.

in the arrangement shown in it ifthe negative resistance .oompenmtesorxthe lossesin th between; ca

This. he so adjusted oscillations {of or the cathode 2.

described is used for be so oscillations will be produced of a frequencyslightlydiderent above described, v the circuit should v he-approximately equal in value to thenega 'll then combine to pmgenitiveresistance of the circuit. a t ode and third electrode. In"

the; odification shown in Fig. 2 l have-in,-

,dicated means for also for the losses in the resonant receiving circuitand the, antenna. In this case-the discharge con- ,muount of energy thustrans trolling .member 6, instead of being connected directly to thecathode 3, is connected to a suitably selected point 17 in the resistanc 18 which is in series with the negameans of this resistancecoupling'ener is-fed back from the negative resistance circuit to theresonant receiving circuit and by properly adjusting the oint 17, the

made suflicient to compensate for the losses in .the receiving circuitand in the antenna without producing oscillations.

A battery 19, ma'y be included in this circuit in order to adjustthenormal potential of the mem: her 6 to a valueat which it will operatemost efliciently. Under these circumstances, the antenna coupling ma beas close and 7 its resistance as lar'e as esired.

WhileIKI have il ustratedand described only two modifications of minvention, it is by no means limited to t e precise ciroeuitarrangements shown as many modifi-' cations in-the connections may bemade without departing from the'scope ofmy invention, as set forth inthe ap ended claims.

What I claimlas new. and esire to secure by LettersPatent. of the UnitedStates, is

"1. The combination in a wireless receiving system of an electrondischarge device *tpntmlling member inclosed in com rising anelectronemitting cathode, an ano e, a third electrode and a! discharge anevacuated receptaclejsources oipote'ntial a plied to said electrodes ofsuch values that t e device has a ne tive resistance between cathodejandthir electrode which varies inversely as the potential applied to, thedis charge controllm member, and means for I v applym recelv c controllir'r'g memben" v I com rising an electronlemitting cathode, an a thirdelectrodef and} a discharge an) e, v. controlling member lnclosed m anevacuated waves to-the discharge- 2. The combinationin a wirelessreceiving system of an electroncdischarge device receptacle, sources ofpotential applied to said electrodes of such valuesthat the. de-

- Vi08 'hfiS"' a negative f resistance betweenv cathode and thir 'lectroe which varies inversely asthe'lpgtential applied to the dis- ;ccha'rgeIvcontrol g member, means fomaperred may be quency.

plying received waves to the' discharge controlling member and capacityand induc-- tance connected in said external circuit and so adjustedthat the circuit is resonant to a desired radio frequency.

3. The combination in a wireless receiving system of an electrondischarge device comprisin an electron emitting cathode, an aim e, athird electrode and a discharge controllin r member inclosed in anevacuated reccpt-ac e, sources of potential applied to said electrodesof such values that the device has a negative resistance betweencathode-and thlrdelectrode whlch varles inversely as the.

potential applied to the discharge controlling "member,. mea-ns forapplying received waves to the discharge controlling member,

a telephone receiver in said external circuit and a capacity shuntingsaid receiver and haring a value so related to the inductance ,of thereceiver that the circuit is resonant to a desired audio frequency.

4. The combination in awireless receiving system of an electrondischarge device com prising'an electron emitting cathode, an anode, athird electrode and a discharge controlling member inclosed in anevacuated receptacle, sources of potential applied -,to said electrodesof such. values that the device has a negative resistance betweencathoderand third electrode which varies" inversely as the potentialapplied to the discharge controlling member, means for applying receivedwavestothe discharge controlling member, atelephone receiver in saidexternal circuit and a ca acity shunting said receiver andhavnig a -vau'e so related to the inductance of the receiver that the circuit is Iresonant to a desired audio frequency, and capacity-and inductanceconnected in said external circuit and so adjusted that thecircuit'isresonant to a desired-radio fre- 5. The combination in a.wireless receiving system of an electrom discharge device comprisinganelectron emitting cathode, an

anode, a third electrode and a discharge controlling member inclosed inan evacuated receptacle, sources of potential applied to said electrodesof such value that the device has a negative resistance between cathodeand" third electrode which varies inversely as the potential applied tothe discharge controling member,'.mean for applying received waves tothedischarge controlling member and ca acity and inductance. connected insaid e rnal radio frequency oscillations of a frequency slightlydifferent from thatof the received oscillations will be generated insaid circuit during the operation of the 6. The'comliination in awireless receiving system of an antenna, an electron dischar c evicecomprising an electron emitting ea o'de, an anode, a third electrode anda discircuit and so adjusted that v evacuated onan't circuit J jmember,and

charge controlling inember 4 inclosed -reee1mtac1e, sourcw ot applied tosaid electrodes. of sue values that the dericehas'e negetiveiresistahcebetween cathode and third electrode which lied to raries imgei'sely asthe poteintiel app the discharge controlling member, a res-.

associated with said ontcnnn and: with said discharge controlling memherfor impressing received waves lip on sendfor transferring from means thefirst mentioned circuit to the resonent an erecdttted .agph'ed to s'mdelectrodes of such v' uesthet fee circuit a suflicient emonnt of errergyto cornpensate for the losses 1n that circuit and m ,the antenna. C

. Thecombinatioh iii a wireles receivsystem of 'an e device has a;negative resistance between cathode and. tiersely ms charge controllingmember, e "resonant circuit associated with seid entenne endmfith' saiddiecherge controlling "member for mnponseid member,

preming received weir end-, resistance coupling'gbete een the two m ntentiel :m node, at third electrode and a osed 1ntrve resistanceresonant circuit;

third electrode which varies in-. the potential applied to the dis-.

- my hand this deyof Month,

meme? from" the circuits for transferring eneir v negative. resistancecircuit to e monent circuit to compensate for the circuit and in theantenna;

8. The combination in a system ,of an antenna, an electron diachardevice comp'risin ode, en'anode, a charge controlling member evacuatedreceptacle, sources of in that third electrode and e in'closed in anotentiel t c device has a negative resistance between cathode and thirdelectrode which varies inversely as the potential applied to the discharge controlling member, a resonant circnitv associated with saidantenna and with said discharge controlling member for impressing receved waves upon posltlve reslstmnce in end. a connection from said to apointin' seidl resist: so chosen that energy ance, said 'poi'nti be ngwill he transferred irom the-negative N31853: once eircuit'totheresonant circuit to com- "pensetefor 7 he the antenne.

losses in that circuit and in hereunto set llnwitness whereof; I Vim-V5-t,

ion.

'wireless receiving I e an electron emitting cagidied to said electrodesof such we ues that said member, series with thenegw

